The subject matter disclosed herein relates to ultrasonic testing, and more particularly, a method and system for determining the position of an ultrasonic wedge and a probe.
Nondestructive testing devices can be used to inspect test objects to identify and analyze anomalies in the objects. Nondestructive testing allows an inspection technician to maneuver a probe at or near the surface of the test object in order to perform testing of both the object surface and underlying structure. Nondestructive testing can be particularly useful in some industries, e.g., aerospace, power generation, and oil and gas transport or refining, where inspection of test objects must take place without removal of the object from surrounding structures, and where hidden anomalies can be located that would otherwise not be identifiable through visual inspection. One example of nondestructive testing is ultrasonic testing. When conducting ultrasonic testing, an ultrasonic pulse can be emitted from an ultrasonic transducer of a probe and passed through a test object. Electric pulses can be generated by a transmitter and can be fed to the probe where they can be transformed into ultrasonic pulses by ultrasonic transducers. In some applications, the probe can be mounted on an ultrasonic wedge that provides intermediary physical contact between the ultrasonic transducer and the test object.
One type of ultrasonic transducer—a phased array transducer—comprises a plurality of electrically and acoustically independent transducer elements that incorporate piezoelectric ceramics. During operation, electrical waveform pulses are applied to the electrodes of the phased array transducer elements of the probe causing a mechanical change in the condition of the piezoelectric ceramics and generating ultrasonic signals (e.g. ultrasonic beams) that can be transmitted through the material to which the probe is coupled. By varying the timing of the electrical waveform pulses applied to the phased array transducer elements, the phased array transducer can generate ultrasonic beams at different angles, allowing the phased array transducer to steer the ultrasonic beam at different angles through the test object to try to detect anomalies. When an ultrasonic beam reflected from the material under inspection contacts the surface of the piezoelectric ceramic of a phased array transducer element, it generates a voltage difference across the electrodes that is detected as a receive signal by signal processing electronics. As the ultrasonic beams pass through the object, various pulse reflections called echoes occur as the ultrasonic beams interact with internal structures (e.g., anomalies) within the test object. By tracking the time difference between the transmission of the electrical pulse and the receipt of the electrical signal, and measuring the amplitude of the received ultrasonic signal, various characteristics of the material can be determined. These echoes allow the depth and size of anomalies within a given test object to be determined.
Another type of transducer—a time of flight diffraction (TOFD) transducer—comprises a transducer element that generates an ultrasonic beam that can be transmitted through the material to which the transmitter probe is coupled and received by another TOFD transducer in the receiver probe. The receiver probe will receive a lateral wave that travels along the surface between the transmitter probe and the receiver probe, and a back wall echo from the reflection of the ultrasonic beam off of the back wall. If the ultrasonic beam encounters any anomalies (e.g., a crack), the receiver probe will also receive a diffracted wave from the upper tip of the crack and a diffracted wave from the lower tip of the crack. These diffracted waves allow the depth and size of the anomaly to be determined.
In order to conduct the ultrasonic inspection of the test object, it is necessary to “set up” the inspection, including the precise position of the ultrasonic wedge and probe. For example, in order to conduct an ultrasonic inspection of a girth weld between two conduits using a phased array transducer, a technician must determine the position of the ultrasonic wedge and probe so that the ultrasonic scan sufficiently covers the weld and the areas of the conduits affected by the heat of the weld (i.e., the heat-affected areas) as well as determining the number of ultrasonic scans required. Similarly, in order to conduct an ultrasonic inspection of a girth weld between two conduits using a pair of TOFD transducers, a technician must determine the position of the ultrasonic wedges and probes so that the ultrasonic scan sufficiently covers the weld and the heat-affected areas of the conduits as well as determining the number of ultrasonic scans required. Once the position of the ultrasonic wedge and the probe is set, the inspection technician can rotate the devices around the conduits to circumferentially scan the girth weld.
A highly skilled and experienced ultrasonic technician employing complex mathematics is typically required to determine the proper position of the ultrasonic wedge and the probe as well as the number of ultrasonic scans. The ultrasonic technician must also locate the ultrasonic wedge and the probe in a manner that complies with industry standards and guidelines for conducting these inspections.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.